Lifting-jack



G. LANE AND G. l. CAMPBELL.

LIFTING JACK.

APPLICATION FILED EEB. 7. 1920.

Patented Mar. 22, 1921.

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LIFTING JACK.

APPLICATION FILED FEB. 1920.

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UNITED STATES PATENT OFFICE.

GEORGE LANE AND GEORGE J. CAMPBELL, 0F PO'UGHKEEPSIE, NEW YORK,ASSIGNORS,`

4BY .DIRECT ANI)` MESNE ASSIGNMENTS, '.IIO` LANE BROTHERS COMPANY, OF

ronenxnnrsrn, NEW' YORK.

LIFTINGJACK.

Patented Mar.`22",`1921.

Application filed `February 7, 1920. Serial No. 356,858.`

To cZZwwm it may concern: i

Be it known that we, GEORGE LANnand (inonen J. CAMPBELL, citizens oftheUnited Stateaandresidents ofthe city of Poughkeepsie, State of New York,have invented certain new and useful Improvements in Lifting-Jacks, ofwhich the following is a specification. p

`Our present invention relates `to improve ments in liftinv' jacks ofthe type shown for `example in etters Patent of the United Statesgranted to Lane Brothers Company,

as assignee of George Lane, yNumbers 1,122,235, 1,181,395 and 1,320,244;

The invention aims tosimplify the con struction and makeit more durableand etti cient in use as will hereinafter appear, and the inventionincludes the novel featuresof construction and arrangement andcombination` of parts hereinafterdescribed and particularly definedbythe appended claims.

In order thatthe invention maybe more readily understood we haveappended hereto drawings illustrating the `preferred embodiments of theinvention in which:

Figure 1 is a sectional elevation ofa suiicent portion of the jack toillustrate the invention.

Fig. 2 is a similar view of the opposite side.

Fig. 3 isa section on line 3-3 of Fig. l.

Fig. 4 isa sectional detail showing the operating handle bar in loweringposition.

Fig. 5 is a detail elevation.

Fig. 6 is a sectional detail showing the handle bar in raising position,and y Figs. 7 and 8 are sectional details of a modification.

Referring by reference characters to these drawings, the standard 2,lifting bar 3, and p actuating or lifting and retaining dogs or pawlsare shown as constructed and arranged to be operated substantially asinthe aforesaid patents, said lifting and retaining dogs being connectedwith the bell crank levers l2 and 11 mounted alongside the actuatinglever 6 and having their contact portions `pressed toward each other bya common spring C In suchprior constructions the connections between thebellv crank levers and dogs were inthe shape ofclose coiled springswhich acted as compression links to transmit the thrust of the C springto the dogs and hold them pressed yieldingly toward the lifting bar`during the lifting operation, the

dogs being pulled away from the lifting bar at the proper time by theaction oflthe contact member 7) striking the bell crank levers androcking themalternately to impart tension `to the springs.

lehave found that these coiledsprings sometimes give trouble in thatthey occasionally buckle and theiloopsithereof getout of place, orbecome disconnected. v

To avoid this objection we substitutefor the connecting springs of the`former `construction, rigid links as shown at 13 `and 14. `VVehavefound, however, that rigid links cannot` be used without somecompensating means, for if the motion of the actuating leverbengainstthe bell crank `lever conuected with a dog or pawl under load, the dogcannot pull out of engagement withthe rack `while the load iszupon it.To avoid this objection in a simple, economical5 efficient and durable`manner `wemake the contact member capable of yielding vertically `whenit strikes a bell crank lever, which permits the actuating lever tocontinue itsmovement until the load on thevdog is relieved. Oneconvenient method of accomplishingthis is to4 support the contact memberZ) onthe end of one arm `of a contact carrying device B, the otherarm ofwhich is journaledin the actuating lever, and is acted upon by a spring22 tending to rock it to keep the contact member normally pressed in onedirecor both of the s arms of the device B in ay be made sufficientlyresilient `to allow -for the vertical yielding movement of the contactportionb above described. The handle bar is indicated at Y and it has aprojection 7c designed to coperate with and shift the contact member'`b.

`Instead of carrying the contact device on the actuating lever it may becarried on the handle bar, and a convenient manner of ac complishingthis is to provide the handle bar 7a, Figs. 7 and 8, with a spring rodB, having one end secured rigidly to the handle bar andthe other endturned at right angles as indicated at and passed through a verticallyelongated slot a in the handle bar, this portion Z2. constituting thevertically yieldable contact member.

In this arrangement the handle bar is shiftable in the socket to alterthe' position ofthe contact portion to determine whether the jack shallrise or lower, though it is obvious that the handle bar might be rigidlyheld and the `rod B shifted relative thereto.

A staple l5 may be provided as additional holding means for the springrod B.

Having thus described our invention what We claim is:

Y. ,1. In a lifting jack, a standard, a toothed lifting bar, anactuating lever pivotally 'mounted on the standard, a pair of pawlscoperating with lthe lifting bar, a member associated with each pawl andpivotally mounted on the standard, a link connection between each memberand its pawl, means 'for yieldably pressing the pawls toward the bar,and a resilient part carried by the lever for engaging said members,said part being placed under tension when moved l toward either of saidmembers if the pawl associated with the latter is carrying the load, andmoving under its tension to shift said member and carry the pawlassociated therewith away from the bar upon the pawl being relieved ofthe load.

2. In a lifting jack, a standard, a toothed lifting bar, an actua-tinglever pivotally mounted on the standard, a pair of pawls coperating withthe lifting bar, a member associated with each pawl and pivotallf.vmounted on the standard, a link connection between each member and itspawl, means for yieldably pressing the pawls toward the bar, and aresilient part carried by the lever for engaging said members, said partbeing placed under tension when moved toward either of said members ifthe pawl associated with 'the latter is carrying the load, and movingunder its tension to shift said member and carry the pawl associatedtherewith away from thebar upon the pawl being relieved of the load,said part being shiftable intoV and out of coperative relation with saidmembers.

3. `A lifting jack comprising a standard. a lifting member guidedthereby, an actuating lever, av pair of actuating pawls coperating withsaid lifting bar, a spring means for normally pressing said pawls intooperative relationto the lifting bar, a rigid push and pull link or rodconnected to each pawl, andmeans for actuating said rods, including avertically yieldable member adapted to be shifted under tensionV and toshift under its tension to actuate said rods,

said member movable longitudinally of the actuating lever. i

4. A jack comprising a standard, a lifting bar, an actuating lever,pawls cooperating with said lifting bar. a pair of spring pressed bellcrank levers pivotally supported from the standard and adapted to presssaid pawls toward the lifting bar, rigid links connecting said bellcrank levers with the pawls, and a contact member movably earried by theactuating lever and having a vertically yieldable contact portionadapted to contact with said bell crank levers in one position 0f thecontact device and to be ineffective as to said bell crank levers inanother position of said device.

5. A jack comprising a standard, a liftingbar, an actuating lever, pawlscoperating with said lifting bar, a pair of spring` pressed bell cranklevers pivotally supported from the standard and adapted to press saidpawls toward the lifting bar, rigid links connecting said bell cranklevers with the pawls, and a. contact member movably carried by theactuating lever and having a `vertically yieldable contact portionadapted to Contact with said bell crank levers in one position of thecontact device and to be ineffective as to said bell crank levers inanother position of said device, and a handle bar for said actuatinglever carrying a part which is movable with respect to said actuatinglever for determining the position of said contact device.

6. A jack comprising a standard, a lifting bar, an actuating lever,pawls coperating with said lifting bar, a. pair of spring pressed bellcrank levers pivotally supported from .the standard and adapted to presssaid pawls toward the lifting bar` rigid links connecting said bellcrank levers with the pawls, a spring arm movably supported b v theactuating lever having a transversely arranged vertically yieldablecontact portion adapted to contact with said bell crank levers in oneposition of said device.

7. A jack comprising a standard, a lifting bar. an actuating lever.pawls coperating with said lifting bar, a pair of spring pressed bellcrank levers pivotally supported from the standard and adapted to presssaid pawls toward the lifting bar, rigid links connecting said bellcrank levers with the pawls, a substantially U-shaped resilient memberhaving one arm pivotally supported by said actuating lever and the otherarm provided with a portion projecting between said bell crank levers, aspring tending to rock said U-shaped member in one direction, and ahandle bar for said socket having a shiftable part adapted to rock saidU-shaped member against the tension of its spring.

8. A jack comprisinga standard, a lifting bar, an actuating lever,pavvls coperat ing with said lifting bar, a pair of spring pressed bellcrank levers pivotally supported from the standard and adapted to presssaid pawls toward the lifting bar, rigid links connecting Said bellcrank levers with the paWls7 an elongated, substantially U- i shapedresilient member, lying in a plane parallel with Said actuating v,leverand having one arm provided with an angularly turned portion pivotallysupported by said i actuating lever and the other arm provided 'with anangularly turned portion projecting between Said bell crank levers, aspring tending to rock said U-sliaped member in one direction, and ahandle bar for said socket having a shiftable part adapted to rook saidU-shaped member against the tension of its spring.

In testimony whereof, we arl'lx our signa tures.

e GEORGE LANE.

` GEO. J. CAMPBELL.

